Cancer is now a leading cause of death by overtaking heart disease in the 21st century. So, the prevention, diagnosis and treatment of cancer are major concerns in the whole world. Korea is not an exception. Since 1988, cancer has been the leading cause of death in Korea. In the case of stomach cancer, it has been reduced in America and European countries but it still exhibits the highest outbreak frequency in Korea and Japan. According to the report of Cancer Registry, Seoul, Korea (1992-95), stomach cancer patients take 23% of total cancer patients (male: 24.7%, female: 17.3%). The average age of outbreak is 54, mostly 40-60 but the age of 20 s takes approximately 3% and the frequency of the disease in men is double that in women. However, once it is early diagnosed, survival rate is at least 90%, suggesting that early diagnosis of stomach cancer is very important for the National Health Care Surveillance.
Tumorigenesis, progress and malignant change are the result of combined action of both genetic factors and environmental factors to result in proteome changes. The correlation between the level of molecular concentrations of proteins, directly involved in essential metabolism and regulation pathways for the survival of every cells including cancer cells, and the relevant mRNA level is very low (correlation coefficient=0.48), so the mRNA focused approach based on high-throughput screening of a target gene might lead to misunderstanding on the biological functions of the target protein. The activity, stability, intracellular location and turnover of the protein involved in cell survival, differentiation and death are regulated by diverse post-translational modifications (PTM). Thus, it is more important to analyze proteome than to focus on mRNA.
Cancer is a systemic disease, in which rather many functions and biological processes of various organs than one or two kinds of cells or tissues are involved. Therefore, such clinical samples, which are able to reflect the whole proteome changes, such as, in serum or body fluid, have to be examined. In fact, general clinical diagnosis has been made through the analysis of the body fluid. So, developing a novel diagnostic method using body fluid that facilitates the effective primary screening might pave the way to significant improvement of survival rate of cancer patients.
The combination of biotechnology (BT) and information technology (IT) gave birth to bioinformatics and bioelectronics that facilitate easy, fast and effective analysis of huge amount of data. Particularly, bioinformatics is a technique to collect, store and analyze huge amount of information that a living body contains, and to use such information in the field of drug development, food production, agriculture and environmental business, etc, resulting in the establishment of biological information S/W, biological information service, and information technology infrastructure. The image mining is a new database applying technique, which is technical combination of image database technique and data mining technique. Unlike the general data mining tried in the field of bioinformatics, the image mining is a novel technique never tried before in domestic and overseas. General data mining techniques are based on applied statistics, suggesting that it is limited in obtaining precise relevant information. For example, proteome spots, seen on the image made by two-dimensional gel electrophoresis, are expected to include information on the disease condition (normal or ill) and various characteristics of the patient. So, if it is possible to extract relevant information by using the image mining technique, diagnostic method and prediction of prognosis, depending on stage and histopathological classification, will be significantly improved and/or complemented.
Korean Patent No. 2004-0055893 describes the automatic template generation method for constructing protein interaction networks, and Korean Patent No. 2003-0092462 describes the method and kit for diagnosis of progress stage of cancer by investigating the level of p53 protein or Bcl-X L protein or the correlation of the two and Bcl-2 protein. However, these two descriptions do not include the explanations on the stomach cancer marker development by using two-dimensional gel electrophoresis and bioinformatics.